1. Field of the Invention
The present invention relates to the fabrication and handling of precast concrete panels. More particularly, the invention is directed to an anchor positioning assembly for forming a recess in a face of a concrete panel and for the simultaneous positioning of an anchor within the recess.
2. Description of the Prior Art
Precast concrete construction includes the prefabrication of concrete wall panels. It is well known in the art to use recessed anchors in such concrete panels wherein external hoisting devices are engagable with the anchors for moving the panels to desired locations. Each panel is typically carried by a mobile crane to its final position where it is temporarily braced until tied into a roof and floor system to become an integral part of the completed structure.
The anchors are preferably recessed from an outer surface of the concrete panel thereby eliminating the need for a subsequent anchor cutting operation after the concrete panel has been hoisted to its intended location. Various devices, typically called xe2x80x9cvoid formersxe2x80x9d, have been proposed for the positioning of anchors within the recesses of concrete panels. Many of these void formers include open interior portions facing outwardly away from the concrete panel to facilitate the insertion of tools therein for removing the void former from the hardened concrete panel while leaving the anchor embedded within the concrete panel. However, during the formation of the precast concrete panel, the open interior portions of the void former may be filled with concrete so that tools may not be effectively inserted, thereby making it difficult to remove the void former from the concrete panel.
While covers cooperating with the top of the void formers have been proposed, an inadequate seal is often formed between the void former and the cover such that concrete still flows into the open interior portions of the void former. Further, conventional covers must be secured to the void formers prior to mounting to the formwork used to define the mold for forming the concrete panel. As such, the entire anchor positioning assembly including the cover, the void former and the anchor must be mounted to the formwork at the same time. This is often a difficult and time consuming task.
Finally, traditional void formers are adapted for use with only an anchor of a particular design, i.e. size and shape. Therefore, different void formers are often required depending upon the particular dimensions of the anchor to be embedded within the concrete panel.
Accordingly, there is a need for a void former and cooperating cover having a structure which substantially prevents the flow of concrete into the interior of the void former. Further, there is a need for such a cover which may be directly mounted to the concrete panel formwork wherein the void former may be simply and easily secured to the cover fixed to the formwork. Finally, there is a need for a void former that is adaptable for receiving anchors of variable sizes and shapes.
The present invention provides an anchor positioning assembly for use in the casting of a concrete panel. More particularly, the anchor positioning assembly includes a void former which secures an anchor during concrete casting and which is removed from the anchor after casting, thereby leaving a recess within a face of the concrete panel and containing a portion of the anchor.
The anchor positioning assembly includes the void former, a cooperating cover and the anchor. The assembly may further include an adaptor insert for receiving anchors of variable shapes and sizes.
The void former includes a body having first and second portions pivotally connected by a pair of hinge webs and symmetrically disposed on opposite sides of a center plane. The first and second portions each include opposing tapered side walls, an arcuate end wall connecting the opposing side walls, and a substantially open chamber defined by the opposing side walls and the end wall. The opposing side walls connect an upper surface of the void former to an arcuate lower surface of the void former as defined by the end walls.
An anchor placement channel extends upwardly from the lower surface of the void former towards the upper surface. The anchor placement channel is defined by a pair of inwardly facing channel walls and the hinge webs. Each inwardly facing channel wall includes a securing lug wherein the pair of lugs face each other on opposite sides of the center plane.
Each of the first and second portions includes a cylindrical rib defining a receiving bore extending upwardly from the arcuate end wall within one of the chambers. Strengthening ribs extend outwardly from each cylindrical rib to interconnect the arcuate lower surface, side walls and inwardly facing channel wall of each of the first and second portions of the body. The cylindrical and strengthening ribs provide additional strength and structural stability to the void former. A locating recess is centrally disposed within the void former and extends downwardly from the upper surface.
A peripheral edge is defined by the opposing side walls and the end walls of the first and second portions of the void former. A first locking member, preferably a peripheral lip, is supported by the opposing side walls and the end walls adjacent the upper surface. The peripheral lip extends proximate at least a portion of the peripheral edge of the void former intermediate a plurality of mounting tabs which are formed integral with the opposing side walls. The mounting tabs include apertures to facilitate fixing of the void former to conventional formwork using nails or similar fasteners.
The cover cooperates with and sealingly engages the void former. The cover includes a top plate having a peripheral edge, and a pair of cylindrical pegs extending downwardly from the top plate. The cylindrical pegs are slidably receivable within the receiving bores of the void former. A locating wall arranged in a rectangular configuration similarly extends downwardly from the top plate and is slidably receivable within the locating recess of the void former.
A second locking member preferably comprises a reentrant edge supported by the top plate and positioned proximate at least a portion of the peripheral edge of the cover. The reentrant edge defines a locking groove which is releasably and lockingly engagable with the lip of the void former. The locking groove extends substantially around the cover proximate the peripheral edge and is interspaced by mounting recesses in which the mounting tabs of the void former are receivable. The mounting recesses have apertures which are coaxially aligned with the apertures of the mounting tabs of the void former such that a single nail or fastener may be passed through the coaxially aligned apertures for fixing the anchor positioning assembly to the formwork and provide a seal between the mounting recess and mounting tab. A plurality of cover mounting apertures are likewise provided proximate the periphery of the cover for mounting the cover to the formwork independently of the void former.
The anchor is received within the anchor placement channel of the void former. A pair of recessed portions are provided within opposing sides of the anchor. The recessed portions preferably interconnect to form an aperture extending through the anchor. The securing lugs of the void former are receivable within the aperture of the anchor for releaseably locking the anchor within the void former.
The adaptor insert may be received within the anchor placement channel for positioning anchors of various shapes and sizes within the void former. The adapter insert is preferably U-shaped and includes first and second legs connected by a bridge. The adapter insert is releaseably securable within the anchor placement channel and provides an inner surface conforming substantially to the upper end of an anchor positioned within the void former.
Therefore, it is an object of the present invention to provide an anchor positioning assembly for forming a recess within a concrete panel and for simultaneously positioning an anchor within the recess.
It is a further object of the present invention to provide a void former which is inexpensive and disposable.
It is another object of the present invention to provide a cover which may be utilized with a wide variety of different void formers.
It is yet another object of the present invention to provide a void former cover having a structure facilitating independent mounting to preexisting formwork.
It is a further object of the present invention to provide an anchor positioning assembly including a cooperating cover and void former where the void former may be snap-locked into releaseable engagement with the cover.
It is still yet another object of the present invention to provide such an anchor positioning assembly which facilitates improved sealing engagement between the void former and the cover.
It is a further object of the present invention to provide a void former having a structure enabling it to accept anchors having a wide variety of shapes and sizes.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.